We explore “10 things” that range from the menu of materials available to engineers in their profession to the many mechanical and electrical properties of materials important to their use in various engineering fields. We also discuss the principles behind the manufacturing of those materials.
By the end of the course, you will be able to:
* Recognize the important aspects of the materials used in modern engineering applications,
* Explain the underlying principle of materials science: “structure leads to properties,”
* Identify the role of thermally activated processes in many of these important “things” – as illustrated by the Arrhenius relationship.
* Relate each of these topics to issues that have arisen (or potentially could arise) in your life and work.
If you would like to explore the topic in more depth you may purchase Dr. Shackelford's Textbook:
J.F. Shackelford, Introduction to Materials Science for Engineers, Eighth Edition, Pearson Prentice-Hall, Upper
Saddle River, NJ, 2015

PC

This course was alot more educational then I thought it would be but now I compare what has shaped me in in life to creep deformation. I especially loved the lecture " a play on good and evil".

AP

Jun 24, 2018

Filled StarFilled StarFilled StarFilled StarFilled Star

Beautiful course. Helped me a lot in the selection of materials for our rocketry team. I'll be sure to suggest this course to my fellow teammates. A big thumbs-up to UCDAVIS for this course.

From the lesson

Making Things Fast and Slow / A Brief History of Semiconductors

Welcome to week 5! In lesson nine we’ll deal with how to make things fast and slow. We’ll examine the lead-tin phase diagram and look at its practical applications as an example of making something slowly. Then we’ll evaluate the TTT diagram for eutectoid steel, and compare diffusional to diffusionless transformations with the TTT diagram, monitoring how we make things rapidly. Lesson ten is a brief history of semiconductors. Here, we discuss the role of semiconductor materials in the modern electronics industry. Our friend Arrhenius is back again, and this time we’re applying the Arrhenius Relationship to both intrinsic and extrinsic semiconductors. We’ll also look at combined intrinsic and extrinsic behavior.

Taught By

James Shackelford

Distinguished Professor Emeritus

Transcript

And so we've talked in some detail in this segment about phase diagrams, those maps of very slowly developing microstructures, that could be monitored through the slow cooling through those phase diagram maps. Probably want to switch, though. We talked about making things fast and slow. Let's talk about the slow equilibrium process mapped out by phase diagrams. I want to talk in some detail about doing things fast. Just like life itself, we seldom do things slowly and as carefully as we might, but in this case, we're actually going to talk about doing things rapidly but in a very controlled way. What we have to keep in mind, as we go through this fast processing of materials, what's generally call the heat treatment of materials. And looking at a very important example again, a followup to that discussion of the Eutectoid reaction in steel technology is that we really have two factors of play. Let's think in terms of simply cooling down a material, a pure material, below its melting point. Really the end points of one of those phase diagrams we looked at earlier. So let's say for a pure component A, perhaps pure metal A, as we cool down below the melting point, the phase diagram simply tells us that we go from a molten liquid to a solid. However, the reality is as we cool below the melting point, whereas the material Is going to transform into a crystalline solid. It's going to do that again under two opposing factors. First of all, as we go lower and lower in temperature below the melting point, the instability of that liquid becomes greater. For those of you familiar with thermodynamics, that thermodynamic driving force becomes larger and larger. On the other hand, one thing we've seen repeatedly in this introductory materials course and beyond in our everyday lives is that we go to higher temperatures, thermally activated processes tend to happen more rapidly and at a exponentially faster rate. So as a result, again, two opposing factors increasing instability, greater driving force as you go to lower temperatures, but slower diffusional processes. So in fact, there's a kind of intermediate temperature at which a particular transformation, let's say the crystallization of a liquid molten metal. There's an intermediate temperature at which that's going to happen at the most rapid rate, just below the melting temperature that transformation will occur very slowly. At very low temperatures that transformation will occur very slowly. At an intermediate temperature, we will see that it's optimized. And we use this simple laboratory furnace here in our teaching laboratories to demonstrate that. We do the heat treating of brass samples, putting small brass samples in here, holding them for a period of time at a given temperature, and then cooling rapidly into air, or into a cooling liquid in order to accelerate that cooling. Well, in those cases we can then monitor the crystal structures that occur and then measure the mechanical properties. So again we are going to turn to a video lecture in which will see these concepts. This trade off between stability and diffusion played out in a very important steel system and how we can then heat treat a so-called eutectoid steel by balancing those two considerations.

Explore our Catalog

Join for free and get personalized recommendations, updates and offers.